6 files changed, 13 insertions, 0 deletions
diff --git a/src/gen-s-parser.inc b/src/gen-s-parser.inc
index 9c3fa90e4..7001cb10b 100644
--- a/src/gen-s-parser.inc
+++ b/src/gen-s-parser.inc
@@ -3159,6 +3159,9 @@ switch (op[0]) {
                   default: goto parse_error;
                 }
               }
+              case 'i':
+                if (strcmp(op, "string.is_usv_sequence") == 0) { return makeStringMeasure(s, StringMeasureIsUSV); }
+                goto parse_error;
               case 'm': {
                 switch (op[18]) {
                   case '1':
diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index cf4e6c9e9..ec9926a30 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -2253,6 +2253,9 @@ struct PrintExpressionContents
       case StringMeasureWTF16:
         printMedium(o, "string.measure_wtf16");
         break;
+      case StringMeasureIsUSV:
+        printMedium(o, "string.is_usv_sequence");
+        break;
       default:
         WASM_UNREACHABLE("invalid string.measure*");
     }
diff --git a/src/wasm-binary.h b/src/wasm-binary.h
index f89391186..97f6bc24e 100644
--- a/src/wasm-binary.h
+++ b/src/wasm-binary.h
@@ -1146,6 +1146,7 @@ enum ASTNodes {
   StringEncodeWTF16 = 0x87,
   StringConcat = 0x88,
   StringEq = 0x89,
+  StringIsUSV = 0x8a,
 };
 
 enum MemoryAccess {
diff --git a/src/wasm.h b/src/wasm.h
index 41eaf328a..42de60a98 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -594,6 +594,7 @@ enum StringMeasureOp {
   StringMeasureUTF8,
   StringMeasureWTF8,
   StringMeasureWTF16,
+  StringMeasureIsUSV,
 };
 
 enum StringEncodeOp {
diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index ef564db6e..0ae17f47c 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -7191,6 +7191,8 @@ bool WasmBinaryBuilder::maybeVisitStringMeasure(Expression*& out,
     }
   } else if (code == BinaryConsts::StringMeasureWTF16) {
     op = StringMeasureWTF16;
+  } else if (code == BinaryConsts::StringIsUSV) {
+    op = StringMeasureIsUSV;
   } else {
     return false;
   }
diff --git a/src/wasm/wasm-stack.cpp b/src/wasm/wasm-stack.cpp
index 9a5db2928..e1b093b26 100644
--- a/src/wasm/wasm-stack.cpp
+++ b/src/wasm/wasm-stack.cpp
@@ -2276,6 +2276,9 @@ void BinaryInstWriter::visitStringMeasure(StringMeasure* curr) {
     case StringMeasureWTF16:
       o << U32LEB(BinaryConsts::StringMeasureWTF16);
       break;
+    case StringMeasureIsUSV:
+      o << U32LEB(BinaryConsts::StringIsUSV);
+      break;
     default:
       WASM_UNREACHABLE("invalid string.new*");
   }